Make select Pokémon even more powerful in Pokémon Go by having them Mega Evolve. When the feature launches, Charizard, Venusaur, Blastoise, and Beedrill will have access to their Mega Evolutions, which players can unlock by collecting Mega Energy through Mega Raids. These concepts all connect, making it pretty easy to achieve while you play the game. But how many Mega Pokémon can you have on your team?
Unfortunately, all players are allowed only one Mega Evolved Pokémon when it first launches. If you have a Mega Charizard on your team, you cannot have a Mega Blastoise on your roster. Whenever you attempt to have another Mega Evolved Pokémon in your party, the currently evolved Mega Pokémon reverts to their original form. The new Pokémon takes their place.
It doesn’t prevent you from having several Pokémon that have the potential to go into a Mega Evolved form. You can have multiple Charizards and Blastoise in your roster that can Mega Evolve, but the moment they Mega Evolve, that slot is theirs until another takes their place. The more times your Pokémon goes through the Mega Evolution, the less Mega Energy it takes to evolve them. You might want to pick a favorite to go through that process so they can readily do it, but having multiple ready to Mega Evolve is never a bad thing.